Answer scripts from the folio asked for, without building every folio (stage D5)

The scripting API (scripts and the assistant's live mode) reached a folio
through diagrams(), which builds every folio, for every call. A folio's
own data -- count, title, uuid, title block, border, wire defaults --
now comes from folios(), built or not; a call reading or changing a
folio's items builds that folio, as showing it does (built()); selecting
a symbol by uuid builds the folio the project database places it on.
Search and replace and the continuity check still build every folio.

DiagramContent worked out one wire of each potential when made, which
follows potentials through folio reports and built the folios at the
other end, for every caller; it is now worked out when first asked
(Search and replace asks; a merge asks both sides, as before).

tst_lazyfolios: on a .qetz, a script reads every folio's title, uuid and
border building none (fails with diagrams()), and the symbols and wires
of the folio with the most links to other folios as when built, building
that folio only (27 before potentials were lazy). ctest 96/96 but
modal_quit_regression in both modes: a race in that test (gdb interrupts
the main thread inside malloc while the folio view repaints during the
dialog, master too), 2 of 23 runs here, 0 of 10 on master, passing alone.
342 corpus projects save the same in all four arms, and export the same
wiring list and wire numbers lazily.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sources/SearchAndReplace/ui/searchandreplacewidget.cpp

@@ -307,7 +307,7 @@ void SearchAndReplaceWidget::fillItemsList()
 
 	m_indi_text_qtwi->sortChildren(0, Qt::AscendingOrder);
 
-	for (Conductor *c : dc.m_potential_conductors)
+	for (Conductor *c : dc.potentialConductors())
 	{
 		QTreeWidgetItem *qtwi = new QTreeWidgetItem(m_conductor_qtwi);
 		qtwi->setText(0, c->properties().text);

sources/diagramcontent.cpp

@@ -79,13 +79,7 @@ DiagramContent::DiagramContent(Diagram *diagram, bool selected) :
 					m_other_conductors << c;
 				}
 
-				if (m_potential_conductors.isEmpty()) {
-					m_potential_conductors << c;
-				} else {
-					if (!potentialIsManaged(c->relatedPotentialConductors(true).values())) {
-						m_potential_conductors << c;
-					}
-				}
+				m_potential_candidates << c;
 				break;
 			}
 			case DiagramImageItem::Type:       { m_images        << qgraphicsitem_cast<DiagramImageItem *>(item);       break;}
@@ -379,12 +373,14 @@ DiagramContent &DiagramContent::operator+=(const DiagramContent &other)
 		if(!m_selected_items.contains(qgi))
 			m_selected_items << qgi;
 	
-	for (Conductor *c : other.m_potential_conductors)
+	QList<Conductor *> potentials = potentialConductors();
+	for (Conductor *c : other.potentialConductors())
 	{
 	        QList<Conductor *> c_list = c->relatedPotentialConductors(true).values();
 		c_list << c;
 		if (!potentialIsManaged(c_list)) {
-			m_potential_conductors << c;
+			potentials << c;
+			m_potential_conductors = potentials;
 		}
 	}
 
@@ -402,17 +398,40 @@ DiagramContent &DiagramContent::operator+=(const DiagramContent &other)
 */
 bool DiagramContent::potentialIsManaged(QList<Conductor *> conductors)
 {
+	const QList<Conductor *> potentials = potentialConductors();
 	bool b = false;
 	
 	for (Conductor *c : conductors)
 	{
-		if (m_potential_conductors.contains(c))
+		if (potentials.contains(c))
 			b = true;
 	}
 	
 	return b;
 }
 
+/**
+	@brief DiagramContent::potentialConductors
+	@return one wire of each potential of the wires of this content, worked
+	out the first time it is asked (see m_potential_conductors)
+*/
+QList<Conductor *> DiagramContent::potentialConductors() const
+{
+	if (!m_potential_conductors) {
+		QList<Conductor *> potentials;
+		for (Conductor *c : m_potential_candidates) {
+			bool managed = false;
+			if (!potentials.isEmpty())
+				for (Conductor *related : c->relatedPotentialConductors(true))
+					if (potentials.contains(related)) { managed = true; break; }
+			if (!managed)
+				potentials << c;
+		}
+		m_potential_conductors = potentials;
+	}
+	return *m_potential_conductors;
+}
+
 /**
 	@brief DiagramContent::hasTextEditing
 	@return true if handle a text currently in editing interaction

sources/diagramcontent.h

@@ -19,6 +19,7 @@
 #define DIAGRAM_CONTENT_H
 
 #include <QSet>
+#include <optional>
 #include <QVector>
 
 #include "../qetgraphicsitem/terminalelement.h"
@@ -77,7 +78,6 @@ class DiagramContent
 		QList<Conductor *> m_conductors_to_update;
 		QList<Conductor *> m_conductors_to_move;
 		QList<Conductor *> m_other_conductors;
-		QList<Conductor *> m_potential_conductors;
 		QSet<DynamicElementTextItem *> m_element_texts;
 		QSet<ElementTextItemGroup *> m_texts_groups;
 		QList<QGraphicsItem *> m_selected_items;
@@ -89,6 +89,7 @@ class DiagramContent
 		QList<DiagramTextItem *> selectedTexts() const;
 		QList<ElementTextItemGroup *> selectedTextsGroup() const;
 		QList<Conductor *> conductors(int = AnyConductor) const;
+		QList<Conductor *> potentialConductors() const;
 		bool hasDeletableItems() const;
 		bool hasCopiableItems() const;
 		QList<QGraphicsItem *> items(int = All) const;
@@ -103,6 +104,12 @@ class DiagramContent
 
 	private:
 		int removePinnedGroups();
+			/// The wires potentialConductors() is made from, in order
+		QList<Conductor *> m_potential_candidates;
+			/// One wire of each potential, worked out when first asked:
+			/// following a potential goes through folio reports to other
+			/// folios, building those not built yet (QET_LAZY_FOLIOS)
+		mutable std::optional<QList<Conductor *>> m_potential_conductors;
 };
 QDebug &operator<<(QDebug, DiagramContent &);
 #endif

sources/scripting/qetscriptapi.cpp

@@ -126,7 +126,7 @@ QString QetScriptApi::filePath() const
 
 int QetScriptApi::folioCount() const
 {
-	return m_project ? m_project->diagrams().count() : 0;
+	return m_project ? m_project->folios().count() : 0;
 }
 
 /**
@@ -183,7 +183,7 @@ QStringList QetScriptApi::signatures()
 int QetScriptApi::currentFolio() const
 {
 	if (!m_project) return -1;
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (m_view && m_view->diagram()) {
 		return diagrams.indexOf(m_view->diagram());
 	}
@@ -193,7 +193,7 @@ int QetScriptApi::currentFolio() const
 QString QetScriptApi::folioTitle(int index) const
 {
 	if (!m_project) return QString();
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (index < 0 || index >= diagrams.count()) return QString();
 	return diagrams.at(index)->title();
 }
@@ -207,7 +207,7 @@ QString QetScriptApi::folioTitle(int index) const
 QString QetScriptApi::folioUuid(int index) const
 {
 	if (!m_project) return QString();
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (index < 0 || index >= diagrams.count()) return QString();
 	return diagrams.at(index)->uuid().toString();
 }
@@ -222,7 +222,7 @@ int QetScriptApi::folioIndex(const QString &uuid) const
 	if (!m_project) return -1;
 	const QUuid wanted(uuid);
 	if (wanted.isNull()) return -1;
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	for (int i = 0 ; i < diagrams.count() ; ++i) {
 		if (diagrams.at(i)->uuid() == wanted) return i;
 	}
@@ -232,18 +232,18 @@ int QetScriptApi::folioIndex(const QString &uuid) const
 int QetScriptApi::elementCount(int folioIndex) const
 {
 	if (!m_project) return 0;
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return 0;
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	return content.m_elements.count();
 }
 
 int QetScriptApi::conductorCount(int folioIndex) const
 {
 	if (!m_project) return 0;
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return 0;
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	return content.conductors(DiagramContent::AnyConductor).count();
 }
 
@@ -462,6 +462,19 @@ void QetScriptApi::setLive(QStringList *log)
 	m_live_log = log;
 }
 
+/**
+	@brief QetScriptApi::built
+	@return @p folio, built if it was not yet (QET_LAZY_FOLIOS), as showing
+	it builds it: what a call reading or changing its items needs. A
+	folio's own data (title block, border, wire defaults) needs no build.
+*/
+Diagram *QetScriptApi::built(Diagram *folio) const
+{
+	if (folio && m_project)
+		m_project->buildFolioToShow(folio);
+	return folio;
+}
+
 /**
 	@brief QetScriptApi::findElement
 	@param folioIndex
@@ -472,9 +485,9 @@ void QetScriptApi::setLive(QStringList *log)
 Element *QetScriptApi::findElement(int folioIndex, const QString &elementUuid) const
 {
 	if (!m_project) return nullptr;
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return nullptr;
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	for (Element *elmt : std::as_const(content.m_elements)) {
 		if (elmt->uuid().toString() == elementUuid)
 			return elmt;
@@ -705,9 +718,9 @@ QString QetScriptApi::addElement(int folioIndex, const QString &locationPath, do
 		log(QStringLiteral("qet.addElement: project is read-only"));
 		return QString();
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return QString();
-	Diagram *diagram = diagrams.at(folioIndex);
+	Diagram *diagram = built(diagrams.at(folioIndex));
 
 	// ElementsLocation::setPath() forces ANY path to embed:// as soon as a
 	// non-null project is given, common://custom:// included -- passing
@@ -817,7 +830,7 @@ bool QetScriptApi::deleteElement(int folioIndex, const QString &elementUuid)
 	}
 	Element *element = findElement(folioIndex, elementUuid);
 	if (!element) return false;
-	Diagram *diagram = m_project->diagrams().at(folioIndex);
+	Diagram *diagram = built(m_project->folios().at(folioIndex));
 
 	DiagramContent content;
 	content.m_elements << element;
@@ -906,9 +919,9 @@ QStringList QetScriptApi::elementUuids(int folioIndex) const
 {
 	QStringList uuids;
 	if (!m_project) return uuids;
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return uuids;
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	for (Element *elmt : std::as_const(content.m_elements)) {
 		uuids << elmt->uuid().toString();
 	}
@@ -1077,7 +1090,7 @@ bool QetScriptApi::addConductor(int folioIndex,
 		return false;
 	}
 
-	Diagram *diagram = m_project->diagrams().at(folioIndex);
+	Diagram *diagram = built(m_project->folios().at(folioIndex));
 	ConductorCreator creator(diagram, terminals);
 	Q_UNUSED(creator)
 
@@ -1110,10 +1123,10 @@ QStringList QetScriptApi::conductors(int folioIndex) const
 {
 	QStringList list;
 	if (!m_project) return list;
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return list;
 
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	const QList<Conductor *> all = content.conductors(DiagramContent::AnyConductor);
 	for (Conductor *c : all)
 	{
@@ -1132,10 +1145,10 @@ QStringList QetScriptApi::conductorUuids(int folioIndex) const
 {
 	QStringList list;
 	if (!m_project) return list;
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return list;
 
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	for (Conductor *c : content.conductors(DiagramContent::AnyConductor))
 		list << c->uuid().toString();
 	return list;
@@ -1152,12 +1165,12 @@ QStringList QetScriptApi::conductorUuids(int folioIndex) const
 QStringList QetScriptApi::conductorEnds(int folioIndex, const QString &uuid) const
 {
 	if (!m_project) return {};
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return {};
 	const QUuid wanted(uuid);
 	if (wanted.isNull()) return {};
 
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	for (Conductor *c : content.conductors(DiagramContent::AnyConductor))
 		if (c->uuid() == wanted)
 			return {describeEnd(c->terminal1), describeEnd(c->terminal2)};
@@ -1787,18 +1800,18 @@ QList<T *> sortedByPosition(const QSet<T *> &items)
 QList<IndependentTextItem *> QetScriptApi::sortedTexts(int folioIndex) const
 {
 	if (!m_project) return {};
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return {};
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	return sortedByPosition(content.m_text_fields);
 }
 
 QList<QetShapeItem *> QetScriptApi::sortedShapes(int folioIndex) const
 {
 	if (!m_project) return {};
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return {};
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	return sortedByPosition(content.m_shapes);
 }
 
@@ -1843,9 +1856,9 @@ int QetScriptApi::addText(int folioIndex, const QString &text, double x, double
 		log(QStringLiteral("qet.addText: project is read-only"));
 		return -1;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return -1;
-	Diagram *diagram = diagrams.at(folioIndex);
+	Diagram *diagram = built(diagrams.at(folioIndex));
 
 	auto *item = new IndependentTextItem();
 	item->setPlainText(text);
@@ -1929,7 +1942,7 @@ bool QetScriptApi::deleteText(int folioIndex, int textIndex)
 	}
 	IndependentTextItem *item = findText(folioIndex, textIndex, QStringLiteral("deleteText"));
 	if (!item) return false;
-	Diagram *diagram = m_project->diagrams().at(folioIndex);
+	Diagram *diagram = built(m_project->folios().at(folioIndex));
 
 	DiagramContent content;
 	content.m_text_fields << item;
@@ -1969,7 +1982,7 @@ int QetScriptApi::addShape(int folioIndex, const QString &type,
 		log(QStringLiteral("qet.addShape: project is read-only"));
 		return -1;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return -1;
 
 	QetShapeItem::ShapeType shape_type;
@@ -1984,7 +1997,7 @@ int QetScriptApi::addShape(int folioIndex, const QString &type,
 		return -1;
 	}
 
-	Diagram *diagram = diagrams.at(folioIndex);
+	Diagram *diagram = built(diagrams.at(folioIndex));
 	auto *shape = new QetShapeItem(QPointF(x1, y1), QPointF(x2, y2), shape_type);
 	diagram->undoStack().push(new AddGraphicsObjectCommand(shape, diagram, QPointF(0, 0)));
 	return sortedShapes(folioIndex).indexOf(shape);
@@ -2116,7 +2129,7 @@ bool QetScriptApi::deleteShape(int folioIndex, int shapeIndex)
 			.arg(folioIndex).arg(list.count()).arg(shapeIndex));
 		return false;
 	}
-	Diagram *diagram = m_project->diagrams().at(folioIndex);
+	Diagram *diagram = built(m_project->folios().at(folioIndex));
 
 	DiagramContent content;
 	content.m_shapes << list.at(shapeIndex);
@@ -2223,7 +2236,7 @@ int QetScriptApi::addPolygon(int folioIndex, const QVariantList &points, bool cl
 		log(QStringLiteral("qet.addPolygon: project is read-only"));
 		return -1;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return -1;
 	if (points.count() < 2) {
 		log(QStringLiteral("qet.addPolygon: at least 2 points are required, got %1")
@@ -2237,7 +2250,7 @@ int QetScriptApi::addPolygon(int folioIndex, const QVariantList &points, bool cl
 		return -1;
 	}
 
-	Diagram *diagram = diagrams.at(folioIndex);
+	Diagram *diagram = built(diagrams.at(folioIndex));
 	auto *shape = new QetShapeItem(poly.first(), poly.last(), QetShapeItem::Polygon);
 	shape->setPolygon(poly);
 	shape->setClosed(closed);
@@ -2321,7 +2334,7 @@ int QetScriptApi::addPath(int folioIndex, const QVariantList &nodes, bool closed
 		log(QStringLiteral("qet.addPath: project is read-only"));
 		return -1;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return -1;
 	if (nodes.count() < 2) {
 		log(QStringLiteral("qet.addPath: at least 2 nodes are required, got %1").arg(nodes.count()));
@@ -2338,7 +2351,7 @@ int QetScriptApi::addPath(int folioIndex, const QVariantList &nodes, bool closed
 		path_nodes << node;
 	}
 
-	Diagram *diagram = diagrams.at(folioIndex);
+	Diagram *diagram = built(diagrams.at(folioIndex));
 	auto *shape = new QetShapeItem(path_nodes.first().anchor, path_nodes.last().anchor,
 								   QetShapeItem::Path);
 	shape->setPathNodes(path_nodes);
@@ -2582,7 +2595,7 @@ bool QetScriptApi::deleteConductor(int folioIndex, const QString &elementUuid, i
 	}
 	Conductor *conductor = findConductor(folioIndex, elementUuid, terminalIndex, caller);
 	if (!conductor) return false;
-	Diagram *diagram = m_project->diagrams().at(folioIndex);
+	Diagram *diagram = built(m_project->folios().at(folioIndex));
 
 	DiagramContent content;
 	content.m_conductors_to_move << conductor;
@@ -2603,10 +2616,10 @@ bool QetScriptApi::removeFolio(int folioIndex)
 		log(QStringLiteral("qet.removeFolio: project is read-only"));
 		return false;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return false;
 	m_project->undoStack()->push(new RemoveDiagramCommand(m_project, diagrams.at(folioIndex)));
-	return m_project->diagrams().count() == diagrams.count() - 1;
+	return m_project->folios().count() == diagrams.count() - 1;
 }
 
 namespace {
@@ -2640,7 +2653,7 @@ const QStringList &titleBlockFieldNames()
 QString QetScriptApi::folioProperty(int folioIndex, const QString &property) const
 {
 	if (!m_project) return QString();
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return QString();
 	Diagram *diagram = diagrams.at(folioIndex);
 	if (property == QLatin1String("template"))
@@ -2665,7 +2678,7 @@ bool QetScriptApi::setFolioProperty(int folioIndex, const QString &property, con
 		log(QStringLiteral("qet.setFolioProperty: project is read-only"));
 		return false;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return false;
 	Diagram *diagram = diagrams.at(folioIndex);
 
@@ -2958,9 +2971,9 @@ bool QetScriptApi::sortTerminalStrip(int stripIndex)
 QList<QetGraphicsTableItem *> QetScriptApi::sortedTables(int folioIndex) const
 {
 	if (!m_project) return {};
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return {};
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	return sortedByPosition(content.m_tables);
 }
 
@@ -3020,7 +3033,7 @@ int QetScriptApi::addTable(int folioIndex, const QString &kind, const QString &n
 		log(QStringLiteral("qet.%1: project is read-only").arg(caller));
 		return -1;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) {
 		log(QStringLiteral("qet.%1: no folio at index %2").arg(caller).arg(folioIndex));
 		return -1;
@@ -3089,7 +3102,7 @@ int QetScriptApi::addTable(int folioIndex, const QString &kind, const QString &n
 	dialog.setAddNewTableToNewDiagram(false);
 
 	const QList<QetGraphicsTableItem *> before = sortedTables(folioIndex);
-	QetGraphicsTableFactory::create(diagrams.at(folioIndex), &dialog);
+	QetGraphicsTableFactory::create(built(diagrams.at(folioIndex)), &dialog);
 	const QList<QetGraphicsTableItem *> after = sortedTables(folioIndex);
 	for (QetGraphicsTableItem *t : after) {
 		if (!before.contains(t)) return after.indexOf(t);
@@ -3105,9 +3118,9 @@ bool QetScriptApi::deleteTable(int folioIndex, int tableIndex)
 		log(QStringLiteral("qet.deleteTable: project is read-only"));
 		return false;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return false;
-	Diagram *diagram = diagrams.at(folioIndex);
+	Diagram *diagram = built(diagrams.at(folioIndex));
 
 	const QList<QetGraphicsTableItem *> all = sortedTables(folioIndex);
 	if (tableIndex < 0 || tableIndex >= all.count()) {
@@ -3381,7 +3394,7 @@ bool QetScriptApi::useConductorAutoNum(int folioIndex, const QString &name)
 		log(QStringLiteral("qet.useConductorAutoNum: project is read-only"));
 		return false;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return false;
 	if (!name.isEmpty() && !m_project->conductorAutoNum().contains(name)) {
 		log(QStringLiteral("qet.useConductorAutoNum: no conductor auto-numbering named '%1'").arg(name));
@@ -3395,9 +3408,9 @@ bool QetScriptApi::useConductorAutoNum(int folioIndex, const QString &name)
 QList<DiagramImageItem *> QetScriptApi::sortedImages(int folioIndex) const
 {
 	if (!m_project) return {};
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return {};
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	return sortedByPosition(content.m_images);
 }
 
@@ -3491,7 +3504,7 @@ int QetScriptApi::addImage(int folioIndex, const QString &filePath, double x, do
 		log(QStringLiteral("qet.addImage: project is read-only"));
 		return -1;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return -1;
 
 	// Same checks as a picture dropped on a folio: a regular file of at
@@ -3503,7 +3516,7 @@ int QetScriptApi::addImage(int folioIndex, const QString &filePath, double x, do
 		return -1;
 	}
 
-	Diagram *diagram = diagrams.at(folioIndex);
+	Diagram *diagram = built(diagrams.at(folioIndex));
 	auto *item = new DiagramImageItem(QPixmap::fromImage(image));
 	diagram->undoStack().push(new AddGraphicsObjectCommand(item, diagram, QPointF(x, y)));
 	return sortedImages(folioIndex).indexOf(item);
@@ -3619,7 +3632,7 @@ bool QetScriptApi::deleteImage(int folioIndex, int imageIndex)
 			.arg(folioIndex).arg(list.count()).arg(imageIndex));
 		return false;
 	}
-	Diagram *diagram = m_project->diagrams().at(folioIndex);
+	Diagram *diagram = built(m_project->folios().at(folioIndex));
 	DiagramContent content;
 	content.m_images << list.at(imageIndex);
 	diagram->undoStack().push(new DeleteQGraphicsItemCommand(diagram, content));
@@ -3675,7 +3688,7 @@ int QetScriptApi::addPdfPage(int folioIndex, const QString &pdfPath, int pageNum
 		log(QStringLiteral("qet.addPdfPage: project is read-only"));
 		return -1;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return -1;
 	if (dpi <= 0) {
 		log(QStringLiteral("qet.addPdfPage: dpi must be positive, got %1").arg(dpi));
@@ -3724,7 +3737,7 @@ int QetScriptApi::addPdfPage(int folioIndex, const QString &pdfPath, int pageNum
 	painter.drawImage(0, 0, rendered);
 	painter.end();
 
-	Diagram *diagram = diagrams.at(folioIndex);
+	Diagram *diagram = built(diagrams.at(folioIndex));
 	auto *item = new DiagramImageItem(QPixmap::fromImage(background));
 	diagram->undoStack().push(new AddGraphicsObjectCommand(item, diagram, QPointF(x, y)));
 	return sortedImages(folioIndex).indexOf(item);
@@ -3948,7 +3961,7 @@ bool QetScriptApi::deleteElementText(int folioIndex, const QString &elementUuid,
 	DynamicElementTextItem *t = findElementText(folioIndex, elementUuid, textIndex,
 												QStringLiteral("deleteElementText"));
 	if (!t) return false;
-	Diagram *diagram = m_project->diagrams().at(folioIndex);
+	Diagram *diagram = built(m_project->folios().at(folioIndex));
 	DiagramContent content;
 	content.m_element_texts << t;
 	diagram->undoStack().push(new DeleteQGraphicsItemCommand(diagram, content));
@@ -4178,7 +4191,7 @@ QStringList QetScriptApi::duplicateElements(int fromFolioIndex, const QStringLis
 		log(QStringLiteral("qet.%1: project is read-only").arg(caller));
 		return created;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (fromFolioIndex < 0 || fromFolioIndex >= diagrams.count()
 		|| toFolioIndex < 0 || toFolioIndex >= diagrams.count()) {
 		log(QStringLiteral("qet.%1: folio index out of range").arg(caller));
@@ -4188,8 +4201,8 @@ QStringList QetScriptApi::duplicateElements(int fromFolioIndex, const QStringLis
 		log(QStringLiteral("qet.%1: no elements named").arg(caller));
 		return created;
 	}
-	Diagram *source = diagrams.at(fromFolioIndex);
-	Diagram *target = diagrams.at(toFolioIndex);
+	Diagram *source = built(diagrams.at(fromFolioIndex));
+	Diagram *target = built(diagrams.at(toFolioIndex));
 
 	QList<Element *> chosen;
 	for (const QString &uuid : elementUuids) {
@@ -4273,7 +4286,7 @@ const QStringList &folioBorderNames()
 QString QetScriptApi::folioBorder(int folioIndex, const QString &property) const
 {
 	if (!m_project) return QString();
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return QString();
 	const BorderProperties b = diagrams.at(folioIndex)->border_and_titleblock.exportBorder();
 	if (property == QLatin1String("columns"))         return QString::number(b.columns_count);
@@ -4412,7 +4425,7 @@ bool QetScriptApi::setFolioBorder(int folioIndex, const QString &property, const
 			.arg(caller, property, folioBorderNames().join(QStringLiteral(", "))));
 		return false;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return false;
 	Diagram *diagram = diagrams.at(folioIndex);
 
@@ -4498,7 +4511,7 @@ QString QetScriptApi::conductorDefault(int folioIndex, const QString &property)
 	if (folioIndex == -1) {
 		p = m_project->defaultConductorProperties();
 	} else {
-		const QList<Diagram *> diagrams = m_project->diagrams();
+		const QList<Diagram *> diagrams = m_project->folios();
 		if (folioIndex < 0 || folioIndex >= diagrams.count()) return QString();
 		p = diagrams.at(folioIndex)->defaultConductorProperties;
 	}
@@ -4524,7 +4537,7 @@ bool QetScriptApi::setConductorDefault(int folioIndex, const QString &property,
 	}
 	Diagram *diagram = nullptr;
 	if (folioIndex != -1) {
-		const QList<Diagram *> diagrams = m_project->diagrams();
+		const QList<Diagram *> diagrams = m_project->folios();
 		if (folioIndex < 0 || folioIndex >= diagrams.count()) return false;
 		diagram = diagrams.at(folioIndex);
 	}
@@ -4633,12 +4646,12 @@ QVariantMap QetScriptApi::terminalPosition(int folioIndex, const QString &elemen
 QVariantList QetScriptApi::conductorPath(int folioIndex, const QString &conductorUuid) const
 {
 	if (!m_project) return {};
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return {};
 	const QUuid wanted(conductorUuid);
 	if (wanted.isNull()) return {};
 
-	DiagramContent content(diagrams.at(folioIndex), false);
+	DiagramContent content(built(diagrams.at(folioIndex)), false);
 	for (Conductor *c : content.conductors(DiagramContent::AnyConductor)) {
 		if (c->uuid() != wanted) continue;
 		QVariantList points;
@@ -4673,14 +4686,14 @@ int QetScriptApi::insertFolio(int position)
 		log(QStringLiteral("qet.insertFolio: project is read-only"));
 		return -1;
 	}
-	if (position < 0 || position > m_project->diagrams().count()) {
+	if (position < 0 || position > m_project->folios().count()) {
 		log(QStringLiteral("qet.insertFolio: position %1 is outside 0..%2")
-			.arg(position).arg(m_project->diagrams().count()));
+			.arg(position).arg(m_project->folios().count()));
 		return -1;
 	}
 	Diagram *diagram = m_project->addNewDiagram(position);
 	if (!diagram) return -1;
-	return m_project->diagrams().indexOf(diagram);
+	return m_project->folios().indexOf(diagram);
 }
 
 /**
@@ -4760,7 +4773,7 @@ int QetScriptApi::addFolio()
 	}
 	Diagram *diagram = m_project->addNewDiagram();
 	if (!diagram) return -1;
-	return m_project->diagrams().indexOf(diagram);
+	return m_project->folios().indexOf(diagram);
 }
 
 bool QetScriptApi::setFolioTitle(int folioIndex, const QString &title)
@@ -4770,7 +4783,7 @@ bool QetScriptApi::setFolioTitle(int folioIndex, const QString &title)
 		log(QStringLiteral("qet.setFolioTitle: project is read-only"));
 		return false;
 	}
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return false;
 	Diagram *diagram = diagrams.at(folioIndex);
 
@@ -5202,7 +5215,15 @@ QVariantList QetScriptApi::checkContinuity(int folioIndex)
 bool QetScriptApi::selectElement(const QString &elementUuid)
 {
 	if (!m_project) return false;
-	for (Diagram *diagram : m_project->diagrams()) {
+		//The folio the project database places it on, built; every folio
+		//when it places it on none
+	QList<Diagram *> folios;
+	const QSet<QUuid> on = m_project->dataBase()->folioUuidsOfElements({QUuid(elementUuid)});
+	for (Diagram *diagram : m_project->folios())
+		if (on.contains(diagram->uuid())) folios << built(diagram);
+	if (folios.isEmpty())
+		folios = m_project->diagrams();
+	for (Diagram *diagram : std::as_const(folios)) {
 		DiagramContent content(diagram, false);
 		for (Element *elmt : std::as_const(content.m_elements)) {
 			if (elmt->uuid().toString() == elementUuid) {
@@ -5218,7 +5239,7 @@ QStringList QetScriptApi::selectedElements(int folioIndex) const
 {
 	QStringList list;
 	if (!m_project) return list;
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return list;
 	for (QGraphicsItem *item : diagrams.at(folioIndex)->selectedItems()) {
 		if (item->type() == Element::Type) {
@@ -5232,7 +5253,7 @@ QStringList QetScriptApi::selectedElements(int folioIndex) const
 void QetScriptApi::deselectAll(int folioIndex)
 {
 	if (!m_project) return;
-	const QList<Diagram *> diagrams = m_project->diagrams();
+	const QList<Diagram *> diagrams = m_project->folios();
 	if (folioIndex < 0 || folioIndex >= diagrams.count()) return;
 	diagrams.at(folioIndex)->clearSelection();
 }

sources/scripting/qetscriptapi.h

@@ -25,6 +25,7 @@
 #include <QVariantMap>
 
 class QETProject;
+class Diagram;
 class DiagramView;
 class Element;
 class Terminal;
@@ -642,6 +643,7 @@ class QetScriptApi : public QObject
 
 	private:
 		bool runFlag(const QString &flag, const QStringList &args);
+		Diagram *built(Diagram *folio) const;
 		Element *findElement(int folioIndex, const QString &elementUuid) const;
 		Terminal *findTerminal(int folioIndex, const QString &elementUuid, int terminalIndex,
 							   const QString &caller);

tests/qttest/lazy_folios_probe.cpp

@@ -30,6 +30,7 @@
 #include "../../sources/ui/elementpropertieswidget.h"
 #include "../../sources/conductorautonumerotation.h"
 #include "../../sources/conductornumexport.h"
+#include "../../sources/scripting/qetscriptapi.h"
 #include "../../sources/wiringlistexport.h"
 #include "../../sources/ui/terminalnumberingdialog.h"
 #include "../../sources/diagramcontent.h"
@@ -800,6 +801,34 @@ int main(int argc, char **argv)
 				check(listed.unloadedFolioCount() > 0, "listing the tables does not build every folio");
 			}
 
+				//A script (and the assistant's live mode) asking about the
+				//folios and one folio's items: that folio built, no other (D5)
+			{
+				QETProject scripted(zipped);
+				const int unbuilt = scripted.unloadedFolioCount();
+				QetScriptApi api(&scripted), usual_api(&eager);
+				check(api.folioCount() == usual_api.folioCount(), "a script counts the folios as when built");
+				for (int i = 0 ; i < folios.size() ; ++i) {
+					check(api.folioTitle(i) == usual_api.folioTitle(i) && api.folioUuid(i) == usual_api.folioUuid(i)
+						  && api.folioBorder(i, "columns") == usual_api.folioBorder(i, "columns"),
+						  "a script reads a folio's own data as when built");
+				}
+				check(scripted.unloadedFolioCount() == unbuilt, "reading the folios' own data builds none");
+					//The folio with the most links to other folios
+				const int target = busiest;
+				check(!scripted.folios().at(target)->isLoaded(), "a folio not built");
+				QStringList lazy_uuids = api.elementUuids(target), usual_uuids = usual_api.elementUuids(target);
+				lazy_uuids.sort(); usual_uuids.sort();
+				check(lazy_uuids == usual_uuids, "a script lists a folio's symbols as when built");
+				QStringList lazy_wires = api.conductors(target), usual_wires = usual_api.conductors(target);
+				lazy_wires.sort(); usual_wires.sort();
+				check(lazy_wires == usual_wires, "a script lists a folio's wires as when built");
+				check(scripted.folios().at(target)->isLoaded(), "the folio a script reads is built");
+				std::printf(".qetz script on folio %d: %d folios built\n", target + 1,
+							unbuilt - scripted.unloadedFolioCount());
+				check(unbuilt - scripted.unloadedFolioCount() == 1, "a script reading one folio builds that folio only");
+			}
+
 				//The wire numbers and wiring list exports, and the terminal
 				//numbering dialog: as when built, building only the folios
 				//holding a terminal (D5)